Chrissy and I visited Gemstone Beach again, arriving just after 3pm, leaving around 5.30pm. It was cloudy, 14 degrees, with a light breeze, and the tide was going out. When we arrived, there were six cars and three campervans in the carpark. It was still a very sandy beach, like it was two days ago, but a couple more patches of stones had been exposed by the waves, one of them just over the Taunoa Stream. We walked down to the Waimeamea River again, this time fording it and spending maybe 15 minutes on the other side.
On our way back, just after recrossing the Waimeamea River, we stopped and chatted with Robyn and Judy who we also met two days ago.
Ten of my finds are featured below. The types of stones we saw on the beach this afternoon were similar to those we saw two days ago. There were very few hydrogrossular garnets and Chrissy found only one very small poppy jasper. Again, there were quite a few trace fossil stones. I did find a number of stones with interesting textures. The most intriguing has spots in it – which is why I spotted it – and the close-up photos suggest it is a spherulitic rhyolite. According to John Farndon’s (2015) book, “Illustrated Guide to Rocks & Minerals”, spherulitic rhyolite originates in “trapped gas pockets of volatile vapours” which develop into “balls of radiating needle-like crystals of quartz and feldspar” (page 64).
See Strekeisen for a relatively techical account of spherulites, along with some great photos and diagrams. This stone is only the fourth spherulitic rhyolite I have found on Gemstone Beach in nine years. In Southland, it is a type of stone much more associated with Slope Point.
Next are three stones with very interesting textures that become apparent in the close-up photos:
When I put stones like this in my bag, I don’t always know how they will look upon closer examination. These three proved to be worthwhile and intriguing specimens.
This afternoon’s best trace fossil stone was found by Chrissy who kindly gave to me, a grey argillite with clearly defined traces in it:
I found this unusual one myself – I’ve not see a trace fossil like this before:
I came across only one small nice hydrogrossular garnet, along with a handful of much smaller and much less interesting ones:
A small colourful quartzy find – white with bright orange, and some brecciation:
A veined green quartzite with a dark irregular central vertical band:
Finally, I always like good specimens of black igneous stones with small white crystals (as in Section 5 in this Post), This find is one of the larger ones I have collected:
Tomorrow I undertake a short fossick on Papatotara Beach. An Index to this Series is here.
